# Geometry: Introduction to Geometry (Level 1 of 7) | Basics

introduction to geometry level 1 geometry is extremely useful for

engineers architects, painters, carpenters teachers, electricians, machinist home builders and many more. Geometric

principles are important in the construction of buildings and roads, the design and use of machinery the creation of three-dimensional

visuals and efects and to better understand and unlock the secrets of the universe

itself like any language and mathematics course the important ideas in geometry must be

developed gradually with understanding practice and effort alright let’s get started with the

basics the simplest figure studied in geometry is called a point although

a point doesn’t have any size it is often represented by a dot which does

have some size but keep in mind that for the most part

they do not have a size we use a dot to visually represent a figure that lack size. We usually name points by using

capital letters for example the following five points are called point A, point B, point C, point D, and point E. All geometric figures

consist of points. another familiar geometric figure is

called a line. Lines are made up of points and are

straight. The arrows on the end of the figures show that the line extend infinitely far

in both directions they extend forever and ever. Although a

picture of a line has some thickness the line itself has no measurable

thickness so keep that in mind unless it is explicitly stated lines have no thickness. The following

figures are example lines there are two different ways we can name

lines the first way is by using a single lower case letter such as line M. The alternative way to name lines is by using their points for example the line in the right contains the points A and B so we can call the line AB using symbols we can denote it like this AB with a line on top or as follows: line BA both ways are acceptable but for the

most part we denote the letters in alphabetical

order so AB will be the typical way to denote this line to talk about the next geometric figure

we need to remember a concept learned in algebra one. In algebra you learned that

a number line is formed when a numerical value is assigned to each point on a line for example the following line represents a

number line and point A is located at negative one,

likewise point B is located at one-and-a-half or

writen another way as one point five. We need to understand number lines in order to understand line segments or

simply segments like lines segments are made up of points and are straight. What

distinguishes them from lines is the fact that line segments have a definite beginning

and end in other words they are measurable they do not

extend for ever and ever in both directions Like lines do. The following are examples of line segments the line segment on the left can be

denoted as: AB or segment BA notice that we add a segment on top of

the letters in order to distinguish it from that of a line which contains arrows in both ends also

notice that a segment is named in terms of its two endpoints because

a segment has a definite beginning and end. The figure in the middle

contains two line segments the vertical up and down segment can be

called RS or segment SR once again we usually denote them in

alphabetical order the horizontal crosswise or from left to

right can be named as segment ST or segment TS. In the following number

line the segment whose endpoint is located at coordinate of negative one and one is denoted as line segment BD or segment DB likewise a segment that has a coordinate at negative two and two is denoted as segment AE or segment EA. So we learn about lines which extend for ever and ever in both

directions and we learn about segments which have a definite length and do not go on

forever and ever is it possible to create a figure that

contains both of these characteristics? the answer is yes. These hybrids are

called rays rays like lines and segments are made up of points and are straight. A ray differs from a line or segment in that it begins at an endpoint and then extends infinitely far in one

direction only lines extend in two directions, rays extend in one direction only so make sure you keep that in mind. The

following are examples of rays now when it comes to denoting them we

actually need to be careful and make sure he start denoting a ray by

naming its endpoint first this way it becomes clear where the ray

begins. So the ray in the left is denoted as ray AB, notice that we add a ray on top

going from left to right this is the appropriate way to denote rays. It

would be completely wrong to denote the ray as ray BA, remember we want to start with

the endpoint first the ray in the right can be called ray RS

or ray RT as long as the end point is

given first any other point on the ray can be used

to denote the ray now that we know about points, lines,

segments, and rays. we can now talk about angles. In essence an angle is made up of two rays with a common end point. this point is called the vertex of the

angle. The rays are called sides of the angle there are various ways that angles can be

described and denoted for example if we place the number one

inside the angle near the vertex like this, we would denote this angle as, angle one the symbol that we used to denote angles

is drawn as follows: its essentially a picture of an angle. If the

angle only contains one letter in the vertex, then you denote it as: angle A. when you denote the angle using one

letter make sure you name the point on the vertex an alternative way is needed if the

angles is described in terms of three points for example, if this angle has a vertex labeled as A and the other points are B and C respectively,

then we need to denote the angle as follows: angle BAC or angle CAB. Notice that when we use three

letters the vertex, in this case A must be

named in the middle make sure you always do this. If we take the

same angle and draw another ray from point A to point D we would end up with three new angles, make

sure you can see them the first angle is formed by points BAD and is denoted as angle BAD or angle DAB. The second angle is denoted as angle DAC or angle CAD and the third angle is denoted as angle BAC or Angle CAB notice that if we try to denote any of the angles

by using only one letter such as angle A, we would be totally

confused what angle we are referring to because all the angles share the same vertex,

so in this case it is really convenient to use three

letters to name the angles alright, the final figure we will talk

about is formed by using three segments and combining them in the following way.

The figure that we just created is called a triangle and we denote it as follows triangle ABC or triangle ACB or triangle CBA or triangle CAB or triangle BAC or triangle BCA. notice that the letters need to start at

one point and move either clockwise or counterclockwise when denoting them. The convenient way is once again by using letters that are in

alphabetical order whenever possible. So triangle ABC will be

the best way to describe this triangle notice that a triangle has three

segments as it sides notice that there seems to be three

angles but hey contain no rays nevertheless, this figure contains three

angles they are angle A angle B and angle C. If you

recall from your algebra class we often talk about sets well it turns out, we can think of a triangle as being a union of three segments and can be denoted

using set notation as follows: triangle ABC is equal to segment AB union with segment BC union with segment AC. Likewise the intersection of any two segments or

sides forms the vertex of a triangle and can be denoted using set notation as follows: vertex A is equal to segment BA intersected with segment AC. Vertex B is equal to segment AB intersected with segment BC and vertex C is equal to segment AC intersected with segment CB. Alright, and there you have it these are the basic building blocks of

geometry and this is only the beginning to recap, we learned about points which

have no size but we draw a point to visually represent one.

We also learned about lines which contain points and extend infinitely

in both directions this is represented by the arrows that

point in both directions we also learned about segments which have

a definite length in other words they are measurable as a consequence they have a beginning

and an end which are called the endpoints of the

segment. We also learned about rays which share the characteristics of a line

and a segment it contains an endpoint in one side

and contains an arrow in the other side which extends infinitely in the direction it is facing. When we have two or more rays that share a common point called a vertex. we form angles and finally when we connect

three line segmens together forming three distinct vertex we create a

triangle. Okay, make sure you’re familiar with all

these figures and the appropriate way to denote and name

them in our next video we will practice denoting and naming figures with various examples.

you sound scandinavian, are you german or austrian?

Thanks. I liked your teaching style. I plan on watching more of your videos.

Thanks! Spread the word about Math Fortress.

Much respect for you, man. Much respect. Thanks for teaching me. Subscribed and liked.

Thanks! You can help the channel and future videos by spreading the word about Math Fortress!

hey dude really nice video and I love your voice ๐

I'm soooo not looking forward to taking geometry D:

Thanks so much! Your teaching style excellent!

No problem please share the channel and let every one know about Math Fortress.

excellent teacher…thank u sooo much for your hard work…

Thank you! Please spread the word about Math Fortress!

Thank you! Please spread the word about Math Fortress!

Thank you! Please spread the word about Math Fortress!

Thank you! Please spread the word about Math Fortress!

Thank you! Please spread the word about Math Fortress.

im going to tenth grade next year and i am so ready to take it on

Im in 10th grade and i want to succeed

Thank you so much for taking your time to explain the beginning as i really wanted it, that was a very nice explanation. Keep it up as you determined to better the lives of our new generations, The Lord Almighty will better your life. …Thanks

Please speak a little slower. But great teaching. Thank you.

This is very helpful! I will look for your other videos

thank you u are making this very easy to understand !

why do you keep asking people to spread the world about math fotress every time they make a comment!?

This is very helpful

I really like your videos

It would be nice if we could scroll the video without having to start from the beginning each time.

angle #dab ๐

It is easy to understand

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Thanks

For sure

Can you tell me about the planes

You are very helpful! Thank You ๐

In hindi language

Oh finally a teacher who knows to tell about why you are leaning something. I am not kidding I have heard of CEOS that if they walk into a meting and they ask what am I going to get out of this meeting? and no one can answer them they walk out. I also most say I have had teachers that when I asked how the average person well use their subject they couldn't tell me.

I got an ad at the beginning about how bad these kinds of videos are ๐๐๐ good job youtube ๐

I am just going to download this and watch it everytime I get confused cause I can't seem to get it and I am in 8th grade

I'm a year ahead in math so I'll be taking geometry as a 9th grader this year! ๐ Thank you

I have to take geometry next year as a sophomore and all the teachers who teach that subject are horrible.

thank you โบ

Very clear and helpful. Thanks.

He said tickness

Don't mind me. I'm just blowing off the cobwebs of my middle school education.

LMFAOOO I GO TO BELL HIGH WHAT OTHER SCHOOL SEND U HERE??

Thank you so much i have a test i forgot to study for tomorrow very helpful

Thank you so much! I just started geometry and didn't have any knowledge of the basics. Now my HW makes sense.

i study in 6th grade but currently learning Karate

Iโm in 7th grade pre algebra and I need to get better

I am year 6 I am gettin ready

Thanks soooo much!! Very helpful! God Bless you!!

I learned and had fun with math from now because of 6:50 (Angle /_Dab) thank you..

I KNOW IT!

im going to secondary school and I want to be prepared since i got a C for my geometry so i want to get an better score!

Good video friend I am 22 and trying to understand earth

Hanzo's tutorial for scatter arrow

Why would a ray begin at the "end point"? If you want math to be easily accessible, that point should be called the "STARTING point"! And don't even get me started on the other math jargon that is used by no one (other than math teachers) and makes any math class a language comprehension challenge rather than a math comprehension challenge. Still, if translated into plain English the video is helpful.

I am in 8th grade and studying for my Honors Geometry final

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0:41 Points

1:17 Lines

2:19 Number Line

2:43 Segments

4:11 Rays

5:28 Angles

7:23 Triangles

Nice explanation

Iโm doing into 8th grade doing geometry looks easy

Imma take geometry in 9th grade bc im advance so im just trying to catch up and be hoping for it to be like a piece of cake. So im hoping when they teach me geometry,I'll be knowing what's on.

iready who?

Thank you Iโm just trying to remember everything for math

๐๐๐

Trying to get ahead for 9th grade!

I took algebra 1 in 9th grade and know I'm getting prepared for Geometry for 10th ๐

Thanks for this lesson. I am in geometry in 9th grade and I am so nervous about everything. On the first day, everyone seemed so smart and more comfortable with geometry than algebra. It honestly makes me confused, isn't algebra the easy one. Haha, that's just my opinion. I still need help on what a dimension is. But I have no doubt that you will allow me to understand easily with these well-detailed and easy to follow along video.

Why can't this make sense๐ญ

I learn more as a 30 year old then when I was 16 hmm

im in 6th grade so this is easy

You are different

You are amazing

This is where Hanzo learned

my math teacher said that geometry lines have 5 letters

I took greomotry in 5th grade had to skip grades fam

With this i will be the best hanzo main

Math isnโt hard,itโs hard to understand but it isnโt hard.Once you fully understand on how to solve a problem then youโll do good

what does Wispytacobot means guys?

Thanks for this video sir. You just helped me alot, i have been taking geometry for the past 5 months and didn't know all these basic things. Once again, thanks alot.

Outstanding ….. Very Helpful…

I dont know how to do that!

The grader for geometry started mouthing off at me one day. I saw a "24" on the test. I also saw that the rest of the test was filled out with pen perfect solutions that made the teacher look inadequate. I think it was really that I was trying to check out one of the problems that she got upset. She said something about "ipsomatic geometry." She was dressed like Daisy Duke. i was going to get up and take the test and point out that the 24 was obviously fake and she was the one grading the tests.

Im in 7th I just want to learn

Weโre currently learning Geometry and I want to learn more. Iโm in seventh grade.

the last part is tricky :…(

My 4th grader is learning this now I don't think I learned this until middle school almost high school

DAB

a point that has no size is basicly space ( wich is dimensionjless)

by the way mother nature doesn't use straight light , like ever. want a way to understand this? try to make straight line soap bubble.the straight line system is only usefull if asomething already exist ( say a rock)

Uh I'm 12

I'm in 8th grade… Am I supposed to be doing Geometry???

basically geoemtry is useful for almost everyone in the world..!

Did video very good thanks lol hahahahahahahahahahah did video not good for me

Never took geometry in highschool because I just.. never got past algebra. And now here I am, as a curious 23 year old who now understands that mathematics and geometry are God's language, but don't know how to read it LOLOL

Im going to take geometry this year (im 13)

And its summer break and I will be using this time to study for geometry

PS:I got 100 in my algebra eoc ๐

The fact is you put spy were in your phones

Why do you not discuss planes, space, and dimensionality here?

anyone else just trying to get a head start during summer before they have to take geometry?

sighI donโt know why, but our school is very advanced. And Iโm a little bit.just a little bit stressed. Our science is like the same level for seniors…(mostly, or probably some) and Iโm still in 6th gradeI think you shouldn't take for granted that someone entering geometry is already familiar with abstract algebra.

I like your explanation

Best way to explain sir…….๐๐

Geometry I need learning so can anyone try and help me